Problem With NewsArticle Rich Snippet

I'm trying to use the NewsArticle rich snippet, to no avail.

I have a WordPress site that uses Yoast. In the header, Yoast puts the Website script as follows:
{"@context":"http:\/\/schema.org","@type":"WebSite",...}

Google seems to read that just fine.

Then, in the body of an article, I have:

<div itemscope itemtype="http://schema.org/NewsArticle">
<meta itemprop="datePublished" content="2015-05-07T18:53:20+00:00"/>
<meta itemprop="image" content="..."/>
etc...


When I run the URL through the Google Tester, it picks up the WebSite part, but not the NewsArticle part.

I do see hentry that contains the proper info, but I was hoping to see a NewsArticle segment. There is none.

Has anyone else seen this? Is there something I'm missing?